The objective of this research is to study the specific molecular structures and molecular interactions found in representative viruses of known chemical composition and morphology. Infrared, Raman and resonance-Raman spectroscopy will be used to determine (1) the amounts and kinds of secondary structure present in nucleic acid and protein components, (2) the state of protonation of key acidic or basic functional groups, (3) the molecular environments of the side groups of key amino acids (e.g. tyrosine and tryptophan), (4) the existence of stabilizing interactions between molecular subgroups (e.g. cytosine and carboxyl groups), (5) the occurrence and configurations of S-H and S-S groups. Such information will be obtained for intact virions and for their constituents as a function of pH, temperature, ionic strength and other factors which perturb structure. Synthesis of these data should give insights into the assembly and disassembly processes for viruses.